This invention relates to a method and apparatus for the processing of shellfish waste meal (SWM). More particularly, to increasing the crude protein while decreasing calcium and phosphorus levels of SWM. The method significantly reduces the percent calcium and phosphorus in shellfish waste meal while lowering the ratio of calcium to phosphorus and raising or maintaining protein levels. These findings make the waste meal a more viable economical protein source in fertilizer and livestock rations.
Proper disposal of aquatic waste is a growing environmental problem for the aqua-culture industry in Louisiana and other coastal areas of the United States. Freshwater Crawfish (Procambarus clarkil) and the White River Crawfish (Procambarus zonangulus) are important commercial commodities in Louisiana. Louisiana produces over 90% of the crawfish harvested in the United States. The state""s aquaculture industry has over 100 crawfish shrimp and crab processing plants. These plants bag the shellfish for sale and or extract the tail meat from the millions of pounds processed at the plants. Of the amount of shellfish harvested each year, approximately 85% (34 to 85 million pounds) is classified as crawfish waste. Analogously, of the crab, and shrimp harvested each year, approximately 60% to 70% is waste respectfully. The exploration of ways to utilize the waste makes good environmental and economical sense.
Shellfish waste is an abundant product emanating from the over 100 crawfish plants in South Louisiana. The reluctance of feed manufacturers to use concentrated amounts of crawfish and other shellfish waste has been due to the high calcium percentage in the meal. More particularly, crawfish waste meal can have an average of 13% to 22% calcium while having a calcium to phosphorous ratio of 18:1 or higher. The percentage of calcium can vary due to the stage of growth of the shellfish and amount of shell in the waste.
The general accepted recommendation in the feed industry is to restrict crawfish or shellfish meal to 10% of the ration for monogastrics and ruminants. The percentage of calcium, phosphorous and the high ratio of calcium to phosphorous and its inhibition of other nutrients are the primary reasons for the feed manufacturers to not seriously consider these meals in their feed rations.
Researchers have attempted to address the problem of commercial shellfish waste but have not found methods which are both economical and ecologically safe. As shown in U.S. Pat. No. 6,153,251 issued to FuKuhara et al. discloses a nutrition-enriched composition for animal feed.
U.S. Pat. Nos. 6,042,464 and 6,102,790 issued to Cowsar et al. shows automated apparatus and method for extracting tail meat from crawfish.
U.S. Pat. No. 5,972,403 issued to Tiller discloses a method for removing salt and water from a fish meal production stream without sacrificing fish protein solids.
U.S. Pat. No. 1,941,001 issued to Braginsky et al. disclose apparatus for the removal and recovery of crustacean meat.
The present invention overcomes the problem of high calcium concentrations and the high calcium to phosphorous ratios normally associated with shellfish waste meal and creates potentially a new revenue stream for the U.S. aquaculture industry.
The invention overcomes the problem of the high calcium and phosphorous counts in shell fish, while significantly reducing the shell fish waste disposal problem in Southern Louisiana. The method allows for the processing of ground shellfish meal into fractionated shell and meal components. The meal component is further processed to a new meal that has a significant reduction in calcium and phosphorous, while maintaining or raising the crude protein in the new crawfish meal product.
Table 1 shows the comparison of unprocessed crawfish waste meal (control) relative to the Method. Table 1 shows that by using the Method, crude protein was significantly increased beyond 50%, while calcium and phosphorous levels were significantly reduce. Conversely, the calcium to phosphorous ratio was also significantly reduced. A major difference in Methods 1, 2 and 3 were the strength of the reagent used in the solution brine. Crawfish waste from the multitude of crawfish plants in South Louisiana and other areas can be converted to crawfish meal and further processed using the Method.
Table 2 shows a comparision of crude protein, calcium, and phosphorous for soybean meal, unprocessed crawfish and processed crawfish. The levels of crude protein are significantly increased for the processed crawfish meal with the calcium and phosphorous levels decreased.
It is an object of the invention to provide a method for increasing the crude protein in shellfish meal.
It is another object of the invention to provide a method to reduce the calcium to phosphorous ratios in shellfish meal.
Another object of the invention is to reduce the annual tonnage of shellfish waste in the United States.
An object of the invention is to provide method of generating a shellfish meal acceptable for use as a fertilizer.
It is another object of the invention to provide apparatus which alows the economical processing of shellfish meal.
Other features and advantages of the present invention will be apparent from the following description in which the preferred embodiments have been set fourth in conjunction with the accompanying drawings.